This application is related to and claims priority from Japanese Patent Applications No. Hei. 11-214222 filed on Jul. 28, 1999, and No. 2000-161821 filed on May 31, 2000, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a bonding method and a bonding structure of a thermoplastic resin material, which can be used, for example, for an adhesion of a thermoplastic resin film to an adherend.
2. Description of the Related Art
It is the common practice to bond a thermoplastic resin film after melting the film and then bonding the molten film to an adherend. This process however involves a problem that upon bonding of the thermoplastic resin film while stacking it on a copper foil or glass epoxy substrate, adhesive strength becomes insufficient.
In view of the foregoing problems, it is an object of the present invention to provide a bonding method and a bonding structure of a thermoplastic resin material, which can improve adhesive strength with an adherend.
According to the present invention, a thermoplastic resin material is disposed on an adherend through a film composed of a dispersing substance which reduces an elastic modulus of the thermoplastic resin material when being dispersed into the thermoplastic resin material, and a position to be adhered is heated to a temperature not less than a glass transition point of the thermoplastic resin material, thereby forming an adhesion-improving layer in which the dispersing substance is dispersed in the thermoplastic resin material, at an interface with the adherend. That is, the thermoplastic resin material is bonded to the adherend through the adhesion-improving layer. Thus, the adhesive strength between the thermoplastic resin material and the adherend is improved.